2,4-D udbredelse og anvendelse

2,4-D is a common and useful active ingredient in many herbicide products used to kill broadleaf plants without harming grasses, especially in lawns and pastures. 2,4-D is available in two forms, an ester and an amine form, which are similar and have the same mode of action. However, the ester form is volatile, which means it easily evaporates into a gaseous form. Once it volatilizes, it can then move easily and quickly on the wind away from the site where it is sprayed. When it comes into contact with grapevines, it will damage their growing portions and fruit.

Workers for Michigan State University Extension have documented occasions when farmers, property owners or commercial pesticide applicators have not been aware of these restrictions, applied the 2,4-D in the ester form and damaged grapes. In each case, this damage to the grape crop resulted in the payment of damages to the growers. Unless you want to pay for part of your neighbor's grape crop, and possibly a fine for the misuse of pesticides, be careful when selecting any herbicide product containing 2,4-D!

A recent study also suggests that 2,4-D exposure may promote antibiotic resistance.

"What makes our study different, is that it is looking at a sub-lethal effect," says Heinemann. "The effect we see requires that the bacteria stay alive."

Previous studies done by other researchers have found that substances chemically similar to dicamba and 2,4-D can cause antibiotic resistance, Heinemann explains. So he and his colleagues decided to investigate whether these herbicides would produce similar effects. They added glyphosate to the study because it is chemically unlike the other two. But, to their surprise, it also produced some antibiotic resistance.

The International Agency for Research on Cancer (IARC), a branch of the World Health Organization, said 2,4-D is "possibly carcinogenic to humans" because there is "strong evidence that 2,4-D induces oxidative stress that can operate in humans and moderate evidence that 2,4-D causes immunosuppression, based on in-vivo and in-vitro studies.

"We have known for decades that 2,4-D is harmful to the environment and human health, especially for the farmers and farm workers applying these chemicals to crops," said Mary Ellen Kustin, senior policy analyst for the Environmental Working Group. "Now that farmers are planting 2,4-D-tolerant GMO crops, this herbicide is slated to explode in use much the way glyphosate did with the first generation of GMO crops. And we know from experience—and basic biology—that weeds will soon grow resistant to these herbicides, making GMO crop growers only more dependent on the next chemical fix."

Konklusion:
Usage of 2,4-D herbicides has been extensive in central Washington
wheat-growing areas for many years. The rapid development of
a grape industry, both Concord and Vinifera, since the early 1960's
has had periodic, widespread damage in vineyards due to drifting
2,4-D. Beginning in the Spring of 1973, programs of 2,4-D monitoring
have been conducted in the lower Yakima Valley of central Washington.
In 1976 a program was begun to test the drift potential of 2,4-D
aircraft spray systems. Correlations between atmospheric monitoring
data, observed vineyard damage, and weather patterns indicate that
long distance transport—10 to 50 miles—is an important factor in
the 2,4-D concentration pattern. Some simple models have been
developed but many questions must be resolved.

In the grape vineyards of Washington there are a number of instances of 2,4-D damage from local drift every year; however this is not the most serious 2,4-D damage situation. In the Washington vineyard area, shown in Figure 1, the 2,4-D damage patterns that caused the major concern are cases where more or less uniform damage symptoms occur at the same time across the vineyards throughout much or all of the grape area. This situation does not have clearly definable gradients and appears to be attributable to the passage of a large, contaminated cloud with the dimensions of miles, at least. Thus this has been labeled as "air mass" damage. Most of the WSU 2,4-D research program has been directed toward finding explanations for this "air mass" damage pattern.

The Threat of 2,4-D Herbicide Drift

One of the characteristics that has limited 2,4-D use in the past is that it will injure or kill many broad-leafed crops, including cotton, soybeans, tomatoes, roses, grapes, fruit trees, and many other home garden crops. It does not have a history of safe use, but rather of one drift accident after another. According to a story in the Des Moines Register, drift from 2,4-D used by farmers after World War II is one of the reasons the Midwest lost its grape industry. More recently, Wisconsin grape growers have lost vineyards to 2,4-D drift, and 250,000 acres of Arkansas cotton were damaged by 2,4-D drift in 2012. In California, 15,000 acres of the San Joaquin Valley were accidentally treated with a fog of 2,4-D in the same year.

In home gardens, herbicide drift damage can occur when a neighbor has their lawn treated with herbicides containing 2,4-D, including granular products. In addition to droplets carried on the wind, damage can occur when the herbicide vaporizes and a persistent chemical cloud forms close to the ground. This is what happened last year to organic farmer Will Reed in Tupelo, Miss., who lost his heirloom tomato crop to herbicide drift that came out of nowhere.

Damage to home gardens from herbicide drift is common enough to merit bulletins from numerous state extension service offices, though gardeners have little hope of recovering their losses. As explained in this advisory from the University of Minnesota, "The 'garden variety' dispute between neighbors is usually not taken through the trial and appeal process, because of the financial realities of paying for lawyers, expert witnesses, scientific analysis, and other litigation costs." There are no public resources for residue testing, which can cost $100 to $300 per sample. Tired of being put in this no-win situation, Iowa farmers who don't want herbicides drifting onto their land are arming themselves with "drift catchers" that capture air samples for analysis.

Rather than forcing organic gardeners and farmers to defend themselves against 2,4-D drift, the USDA needs to change its priorities, get out of bed with Big Ag, and start working to protect our environment and help farmers farm without poisons. Do you feel the push to do something, to share your opinions on GM food crops and ever-present pesticides? You have until midnight on February 24, 2014, to make your voice heard on the deregulation of genetically modified crops that tolerate treatment with 2,4-D. The only thing that will overcome the pressure from chemical companies will be greater pressure from you, the public.